Thermal, bi-modal heat-pump and cushioning shoe insole

ABSTRACT

A bi-modal thermal insole heat pump and shock cushioner which can selectively be reversibly deployed in a shoe to act, with regard to its heat-pump capabilities, either as a heat-deliverer or as a heat-remover with respect to the underside of a user&#39;s foot.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation from regular U.S. patentapplication Ser. No. 10/003,122. filed Nov. 14, 2001 for “CushioningShoe Insole”, which application, as does this continuation applicationalso, claims priority to U.S. Provisional Application Ser. No.60/281,604, filed Apr. 4, 2001 for “Cushioning Shoe Insole”. Both ofthese predecessor and serially copending patent applications are herebyincorporated into this application by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

[0002] This invention relates to a cushioning and thermally active shoeinsole structure, and in particular to insole structure which functionsas a reversible heat pump, depending upon insole orientation, within theconfines of an otherwise conventional shoe.

[0003] A preferred embodiment of the invention is described herein inthe form of a two-layer structure, one side of which can actadvantageously as a heat-delivery side, and the opposite side in whichcan act as a heat-removal, or cooling, side.

[0004] Further, the invention focuses on such an insole structure which,in addition, performs as an extremely effective shock-absorbingmechanism in a shoe.

[0005] A preferred embodiment of the proposed heat-pump insole includesat least one acceleration-rate-sensitive (typically viscoelastic) layerhaving opposite facial expanses, to one of which expanses is bonded alow-friction, wear-resistant, moisture-wicking fabric material.

[0006] We have discovered that such an insole construction uniquelyfunctions as a kind of reversible, passive heat pump, depending uponwhich side of the structure, inside a shoe during use, faces upwardlytoward contact with the underside of a user's foot. Very specificallywhat we have discovered is that when a preferred structure like thatjust generally set forth above is employed inside a shoe, the uncovered“rate-sensitive” side, or surface, of the structure functions as aheat-delivery surface, and the opposite, moisture-wicking-fabric side,or surface, when facing upwardly inside a shoe, acts as a heat-removingand cooling surface.

[0007] While various acceleration-rate sensitive materials may beemployed in the structure of this invention, so-called viscoelasticmaterials which fit within this category have been found to be verysatisfactory. It is for this reason that a preferred embodiment of theinvention is described herein in the context of such a viscoelasticmaterial.

[0008] The various interesting features and important and uniqueadvantages that are offered by the present invention will become morefully evident as the description that now follows is read in conjunctionwith the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a simplified plan view illustrating an isolated shoeinsole which is constructed in accordance with the present invention.

[0010]FIG. 2 is an enlarged and fragmentary side elevation, takengenerally along the line 2-2 in FIG. 1. The small insole fragment whichappears at the right side of FIG. 2 illustrates a modified constructionwherein a cushioning layer structure is made up of more than just asingle specific material.

[0011]FIG. 3 is a view somewhat like that presented in FIG. 2, generallyillustrating how the insole of FIGS. 1 and 2 responds, in relation toits shock-absorbing capabilities, to dynamic loading.

[0012]FIG. 4 is a simplified plan view of a pair of side-by-side insoleheat-pump structures constructed in accordance with the presentinvention, placed inside left and right shoes (not shown) in such afashion that the insole's upwardly facing sides are those sides whichare formed by the fabric material mentioned above.

[0013]FIG. 5 is a simplified and stylized cross-sectional view, takengenerally along the line 5-5 in FIG. 4, and employing two differentstyles of squiggly arrows to picture heat-flow activity engaged in bythese insole heat-pump structures in accordance with this invention.

[0014]FIG. 6 is very similar to FIG. 4, except that here, the same twoinsole heat-pump structures have been turned over (top for bottom) andswitched laterally (left to right) so that they now occupy a pair ofshoes (not shown) wherein their upper surfaces are theviscoelastic-material surfaces mentioned above.

[0015]FIG. 7 is a simplified cross-sectional view, very much like thatpresented in FIG. 5, here also employing two different characters ofsquiggly arrows to illustrate heat-pump activity.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Turning attention now to the drawings, a preferred form of aproposed heat-pump insole structure (or insole) of this invention isindicated generally at 10. This insole is constructed in such a fashionthat it is provided to a user in mirror-image pairs. As was generallydescribed above, and as will be more filly described below, the twoinsoles in a given, supplied pair are essentially mirror-image copies ofone another which can be placed (a) with one set of orientations in aleft and right shoe with a common-structure upwardly facing surface, and(b) with another set of orientations flipped and reversibly placed inleft and right shoes with common opposite facial structure then facingupwardly. With these insoles deployed so that their directly exposed,acceleration-rate-sensitive, viscoelastic sides face upwardly, theinsoles act as heat deliverers to the underside of a user's feet. In theopposite orientation or deployment, flipped over and switched in aleft-to-right manner, and with, now, the moisture-wicking fabricmaterial facing upwardly, the insoles act as heat removers relative tothe undersides of a user's feet.

[0017] In FIGS. 1, 2 and 3, only one mirror-image version of theproposed insole is illustrated. A description of this version willadequately suffice to describe the opposite mirror-image counterpart.

[0018]FIG. 4-7 inclusive illustrate matched pairs of insoles, and howthey can be employed reversibly and bi-modally in accordance with thepresent invention.

[0019] Beginning, therefore, with a description of what is shown in FIG.1, 2, and 3, insole 10 is preferably formed to be employable as a freeinsert for an already constructed shoe, and specifically to be an insertwhich will form-fittingly rest on the bottom inside surface of a shoe,with the perimetral outline of the insole substantially extending to thefull perimetral outline of the inside exposed base area in the shoe.

[0020] Insole 10 includes a heat-flowable, anti-spring-back, shock(acceleration)-rate-sensitive cushioning layer 12, preferably formed ofa material such as the micro-cellular, viscoelastic, urethane materialknown as Poron® 400 Performance Urethane Series 90, Formation #94. Thisparticular material is manufactured by Rogers Corporation in Woodstock,Conn.

[0021] Layer 12, which has upper and lower surfaces 12 a, 12 b,respectively, as seen in FIG. 1, and which is formed preferably from aviscoelastic material like that just specifically identified, has animportant behavioral pattern, or set of capabilities, whereby (a) itdeforms in an acceleration-rate-sensitive manner (the greater theacceleration, the slower the responsive deflection), (b) itself-generates a significant amount of heat as it is subjected torepeated, normal-walking (or running), reversible deformation in use,(c) it returns slowly from such a deformation toward an undeformedcondition without exhibiting any appreciable spring-like mannerisms, and(d) it delivers heat from its broad, outwardly facing, preferablyuncovered surface expanse during its retarded return toward to anon-deformed state, and in fact, throughout the period of time that isit actually in use beneath a user's foot.

[0022] By way of contrast, and specifically discussing contrasts inrelation to shock-cushioning behavior, an undesirable spring-actionresponse to a deflection (which does not occur with respect to thebehavior of layer 12) occurs where a material effectively reacts to, andtends to return from, a force-impact deflected condition with a feltreturn force, and in a time-frame, that generally match those of theevent which has produced the subject deflection. A non-spring-likeresponse, which importantly is characteristic of the behavior of layer12, takes the form of a return (from a shock-force/impact deflection)that is retarded over time, and characterized by a lowered,overall-felt, return-force behavior. In a sense, a material behaving inthis non-spring-like manner tends to “creep” back toward an undeformedcondition, and this is precisely how the material which makes up layer12 in accordance with the present invention behaves in the overallperformance of insole 10. This behavior plays a significant role inminimizing the presence of localized high-pressure contact regionsbetween a shoe, the insole and the underside of a user's foot.

[0023] Another important advantage which is offered by layer 12 in theinsole is that it tends to flow (at a creep) with heat and compression,and thus tends to deform gradually to create an upwardly facing,topographically conforming, foot-support surface which tends tocomplement and follow the configuration of the underside of thesupported foot. This behavior is what enables insole 10 to obviatehigh-pressure contact regions with a user's foot.

[0024] The exposed surface-expanse area of layer 12 which remainsuncovered, so-to-speak, in the final preferred construction of insole 10has a surface frictioning quality which, when stood upon directly (i.e.,directly contacting the underside of a wearer's foot), plays animportant role herein in the generating of friction-induced heat. Thisfriction heat-generating facet of the behavior of layer 12, when coupledwith the layer's above-mentioned propensity to “self-generate” heat as aconsequence of repeated reversible deformations, offers, as the presentinvention proposes, a significant opportunity to employ the insole ofthis invention as a heat-delivering heat-pump.

[0025] Layer 12 herein has a thickness of about {fraction(3/16)}-inches. Variations in this thickness have a bearing on theheat-generating performance of layer 12, with thicker layers generallyacting to generate more appreciable heat than thinner layers. Thus,thickness of this layer offers to designers a performance-variationoption vis-a-vis heat delivery behavior.

[0026] The small fragment of insole 10 which appears at the right sideof FIG. 2 illustrates a modified form of insole, wherein layer 12includes two sub-layers 12 c, 12 d. Each of these layers is formed of anappropriate, through selectively somewhat different, viscoelasticmaterial. This form of the insole provides a somewhat different kind ofbehavior, especially in relation to cushioning and shock-absorbingperformance.

[0027] Suitably surface-bonded to surface 12 a in layer 12 is a thin,fabric, moisture-wicking, low-surface-friction layer 14. Preferably,layer 14 is formed of a woven-fibre fabric material, such as that knownas HEATHERSTONE®, made by Lee Fashion Fabrics, Inc., in Gloversville,N.Y. Fabric layer 14 herein has a thickness preferably of about{fraction (1/64)}-inches, and includes elongate, stretch-resistantfibres (see 14 a in the figures) that function as tension-active,load-distributing components in the fabric.

[0028] Layer 14 plays several important cooperative roles (i.e.,cooperative with layer 12) in insole 10. One of these roles involvesfurnishing a surface which has a low coefficient of sliding friction, soas to minimize friction heat development around the foot of a userduring normal shoe use with layer 14 directly lying beneath a user'sfoot. Another role involves the wicking of moisture which typicallydevelops in a shoe, and carrying this moisture efficiently to the sideedges (perimeter) of the insole where that moisture can quicklyevaporate, and in so doing, provide cooling within a shoe. Yet anotherrole of layer 14 is that its fibres act as elongate load-distributingelements that aid in spreading localized load events to a broader areawithin the insole.

[0029] From the description of insole 10 which has just been given, itwill be apparent that its opposite broad faces, one of which is definedby surface 12 b in layer 12, and other of which is defined by theexposed surface expanse of the fabric material in layer 14, actbi-modally to deliverer or remove heat from the region of contact withthe underside of a user's foot, depending upon which one of thesesurfaces faces upwardly in the manner that the insole is deployed in ashoe. An so, with insole 10 deployed in a shoe with fabric layer 14facing upwardly, this insole acts as a cooling heat-pump. With this sameinsole flipped over, and deployed in the opposite-foot shoe, and withsurface 12 b of layer 12 facing upwardly beneath a user's foot, theinsole acts like a heat-delivery heat-pump. Thus the insole offers theopportunity to provide bi-modal heat delivery or heat removalselectively, and under appropriate wearing conditions, all at the user'scomplete selection.

[0030] While the preferred construction of insole 10 is one wherein side12 b in layer 12 is completely uncovered, an additional modification ofthe invention involves employing a thin fabric layer over this surfaceas a modest modifier of heat-delivery activity. Such a thin layer offabric, which can be thought of as being represented visually in FIG. 2by a thin portion of the line therein designated with referencecharacter 12 a, can be employed to “tone down” the delivery of heat.

[0031] Offered by insole 10 of this invention, along with thejust-expressed important heat-pump capabilities, are shock-handlingqualities which will now be more fully described.

[0032] As was pointed out earlier, the material which makes upcushioning layer 12 responds to shock-force/impact loading in such afashion that it has a tendency to return from a deformation (produced bysuch loading) in a retarded, slow and low-return-force (non-springy)fashion. This “low-return-force” behavior is evidenced by the materialreturning toward an undeformed (unshock-deformed) condition withoutdisplaying anywhere the same level of local return force or pressurewhich characterizes the initial loading per se.

[0033]FIG. 3 is expressly presented to highlight this importantperformance of layer 12 in insole 10. In solid lines in this figure,layers 12, 14 are shown representationally shock-deflected to producethe combined deformation generally indicated as a depression at D.Dash-double-dot-lines show the undeformed, prior dispositions of thelocal upper surfaces of these two layers.

[0034] Short, solid, downwardly-pointing arrow T₁, and long, shaded,downwardly-pointing arrow F₁ represent related time-span andapplied-force characteristics, respectively, of the shock event whichhas produced deformation D. Long, solid, upwardly-pointing arrow T₂, andshort, shaded, upwardly pointing arrow F₂, represent the relatedtime-span and return-force characteristics, respectively, of how layer12, in cooperation with layer 14, will try to return from theshock-deformed state. As can be seen, T₂ is greater in length than isT₁, and F₁ is greater in length than is F₂. These comparative anddifferentiated “lengths” represent the time-span and force-levelbehavioral characteristics which signal the kind of non-spring-factorcushioning response which produces the remarkable cushioning performancethat is offered by the present invention. Fibers 14 a, as indicatedcooperatively by reversed arrows 16 in FIG. 3, act to distribute andspread load laterally in the insole.

[0035] On another point, the several outwardly pointing arrows whichradiate from the letter M in FIG. 1 represent how moisture is wicked bylayer 14 to the lateral (perimetral) edges of insole 10. At theperimeter of the insole, such wicked moisture readily evaporates, andintroduces effective and noticeable cooling in a shoe equipped with theinsole of this invention.

[0036] Shifting attention now to FIG. 4-7, inclusive, FIGS. 4 and 5illustrate schematically and very simply two different points of viewrelating to two, mirror-image insoles 20, 22 which are formed with theconstruction described above for insole 10. These two insoles aredeployed in left and right shoes, respectively, in FIGS. 4 and 5 andvery specifically are deployed in such as fashion that their respectivefabric sides 20 a, 22 a face upwardly to engage directly the undersidesof a user's feet. The exposed viscoelastic sides of these two insoles,shown at 20 b, 22 b, are downwardly facing in the deployment pictured inFIGS. 4 and 5.

[0037] With this deployment of insoles 20, 22 in shoes (not shown), heatis removed from the region beneath a wearer's foot, such heat removalbeing indicated by broad squiggly arrows 24, and heat is vented, orpumped, outwardly and downwardly through the bottom viscoelastic sidesof the insoles, as is indicated by pairs of squiggly arrows 26.

[0038] In FIGS. 6 and 7, matters are reversed. Here, insoles 20, 22 havebeen shifted left to right, placed in the opposite shoes respectingwhere they were as pictured in FIGS. 4 and 5, and have been turned overgravitationally so that their upper surfaces are now the viscoelasticsurfaces. With this deployment of insoles 20, 22, heat is deliveredupwardly to the underside of a user's feet, and is withdrawn from theregion of the interface between the undersides 20 a, 22 a of the insolesand the bottom inside surfaces (upwardly facing but not shown) of therespective, associated shoes.

[0039] Insoles 20, 22 are preferably formed with perimetral outlinesthat are the mirror images of one another with respect to commonlyfacing broad expanse surfaces. They can easily be reversibly deployed,as was just described, in a user's shoes of the appropriate size, thusto give the user an opportunity to utilize the insoles either asheat-delivery heat-pumps, or as heat-removal heat-pumps, depending uponvarious conditions, and as selected by the user.

[0040] The insole structure thus proposed by the present inventionoffers some very special advantages in relation to conventional insoles.Its construction is quite simple, and it lends itself readily toincorporation removably in just about any conventional shoe design. Byselecting the gravitational orientation of a pair of matched insoles,these insoles, when installed and in use, can act selectively either asheat-pump deliverers of heat, or as a heat-pump removers of heat.Heating of the material in layer 12 during normal use, and regardless ofthe gravitational orientation of that layer, causes the portion or thesurface of the associated insole which directly contacts a user's footto form fit with respect to the underside of the foot.

[0041] Acceleration-rate-sensitivity in layer 12 leads to significantanti-spring-back behavior, and contributes to a remarkable ability ofthe insole, in addition to acting as a versatile, reversible (orbi-modal) heat-pump, to cushion shock loads. Fabric layer 14 acts as alow-friction surface in the insole which is especially effective whenthe insole is deployed so as to remove heat from the region ofinterfacial contact between the insole and the user's foot. Themoisture-wicking capability of layer 14 draws moisture away from beneaththe foot, under circumstances with the foot engaging this layer,transporting that moisture to the perimeter of the insole, and thuspromoting heat-removal cooling.

[0042] Accordingly, while the present invention has been disclosed in aparticular setting, and with a particular structural form herein, it isappreciated that variations and modifications may be made withoutdeparting from the spirit of the invention.

We claim:
 1. A bi-modal, reversibly and removably deployable,shoe-insole heat-pump structure in the form of a generally planarplural-layer assembly comprising a heat-delivery layer formed of amaterial wherein deliverable heat develops internally as a consequenceof dynamic deformations that take place in the material during wearinguse inside a shoe, said heat-delivery layer having one facial expansedefining a heat-delivery side for said heat-pump structure, and anopposite facial expanse, and a heat-removal, cooling layer formed of alow-surface-friction, moisture-wicking material having one facialexpanse joined to said opposite facial expanse in said heat-deliverylayer, and an opposite facial expanse defining a heat-removing side forsaid heat-pump structure, said layers, as joined into said assembly,having an appropriate, laterally reversible, left-shoe/right-shoeperimetral outline, depending upon which of the layers constitutes theupper, foot-engaging layer as installed removably in a shoe, whicheverone of the layers that is deployed as the upper layer in a particularuse installation determining whether the wearer experiences heating orcooling with regard to the assembly that includes that layer
 2. Theheat-pump structure of claim 1, wherein said heat-delivery layer isspecifically formed of one or more acceleration-rate-sensitivematerial(s).
 3. The heat-pump structure of claim 2, wherein saidacceleration-rate-sensitive material is a viscoelastic material.